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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

TAB interconnects for space concentrator solar cell arrays

The Boeing Company has evaluated the use of Tape Automated Bonding (TAB) and Surface Mount Technology (SMT) for a highly reliable, low cost interconnect for concentrator solar cell arrays. TAB and SMT are currently used in the electronics industry for chip interconnects and printed circuit board assembly. TAB tape consists of sixty-four 3-mil/1-oz tin-plated copper leads on 8-mil centers. The leads are thermocompression gang bonded to GaAs concentrator solar cell with silver contacts. This bond, known as an Inner Lead Bond (ILB), allows for pretesting and sorting capability via nondestruct wire bond pull and flash testing. Destructive wire pull tests resulted in preferred mid-span failures. Improvements in fill factor were attributed to decreased contact resistance on TAB bonded cells. Preliminary thermal cycling and aging tests were shown excellent bond strength and metallurgical results. Auger scans of bond sites reveals an Ag-Cu-Tin composition. Improper bonds are identified through flash testing as a performance degradation. On going testing of cells are underway at Lewis Research Center. SMT techniques are utilized to excise and form TAB leads post ILB. The formed leads' shape isolates thermal mismatches between the cells and the flex circuit they are mounted on. TABed cells are picked and placed with a gantry x-y-z positioning system with pattern recognition. Adhesives are selected to avoid thermal expansion mismatch and promote thermal transfer to the flex circuit. TAB outer lead bonds are parallel gap welded (PGW) to the flex circuit to finish the concentrator solar cell subassembly.

Avery, J.↗
NASA NTRS2000

Androgen and taxol cause cell type-specific alterations of centrosome and DNA organization in androgen-responsive LNCaP and androgen-independent DU145 prostate cancer cells

We investigated the effects of androgen and taxol on the androgen-responsive LNCaP and androgen-independent DU145 prostate cancer cell lines. Cells were treated for 48 and 72 h with 0.05-1 nM of the synthetic androgen R1881 and with 100 nM taxol. Treatment of LNCaP cells with 0.05 nM R1881 led to increased cell proliferation, whereas treatment with 1 nM R1881 resulted in inhibited cell division, DNA cycle arrest, and altered centrosome organization. After treatment with 1 nM R1881, chromatin became clustered, nuclear envelopes convoluted, and mitochondria accumulated around the nucleus. Immunofluorescence microscopy with antibodies to centrosomes showed altered centrosome structure. Although centrosomes were closely associated with the nucleus in untreated cells, they dispersed into the cytoplasm after treatment with 1 nM R1881. Microtubules were only faintly detected in 1 nM R1881-treated LNCaP cells. The effects of taxol included microtubule bundling and altered mitochondria morphology, but not DNA organization. As expected, the androgen-independent prostate cancer cell line DU145 was not affected by R1881. Treatment with taxol resulted in bundling of microtubules in both cell lines. Additional taxol effects were seen in DU145 cells with micronucleation of DNA, an indication of apoptosis. Simultaneous treatment with R1881 and taxol had no additional effects on LNCaP or DU145 cells. These results suggest that LNCaP and DU145 prostate cancer cells show differences not only in androgen responsiveness but in sensitivity to taxol as well. Copyright 2000 Wiley-Liss, Inc.

NASA Program Fundamental Space Biology↗
NASA NTRS1993

Cycle life status of SAFT VOS nickel-cadmium cells

The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

Goualard, Jacques↗
NASA NTRS1991

Advances in Li-TiS2 cell technology

JPL is involved in a NASA sponsored program to develop ambient temperature secondary cells for future space missions. After several years of research on various cathode materials, Titanium Disulfide (TiS2) was selected in view of its intrinsic reversibility and high faradaic utilization. In the last two years, the efforts were focused on improving the cycle life of the system and developing 1 Ah cells. Several approaches including the use of mixed solvent electrolytes, the operation of cells at low temperature, and the cycling of cells under different voltage limits, were initially examined to improve the cycle life performance of the Li-TiS2 system. Spiral wound 1 Ah cells fabricated incorporating the improvements from the above studies have delivered more than 600 cycles at 50% DOD. Work is in progress to identify alternate anode materials that can improve the cycle life of the cells to 1000 cycles at 50% DOD. This paper summarizes the advances made in the Li-TiS technology at JPL since 1989.

S Surampudi↗
NASA NTRS1978

Conceptual approach study 200 watt per kilogram solar array, phase 3

Activities are described that were directed by JPL to support the earlier conceptual design work with proof of concept models on the one hand, and laboratory test and evaluation of alternate designs and materials that hold promise for further mass economies, on the other. In support of this advanced solar blanket technology the following work was accomplished: (1) preparation of an 80 cell solar module for a 1000 cycle thermal test (2) fabrication of a 660 cell solar panel and performance evaluation of this article after a '0' g flight test, (3) design improvement of the cell interconnect for further mass reduction, (4) completion of UV exposure and thermal cycle tests for a variety of cell cover material and adhesives and (5) preparation of a quantity of representative solar array test specimens for space flight on NASA's Long Duration Exposure Facility (LDEF).

Rayl, G. J.↗
NASA NTRS2001

Detecting Pyrolysis Products from Bacteria on Mars

A pyrolysis/sublimation technique was developed to isolate volatile amine compounds from a Mars soil analogue inoculated with approx. 10 billion Escherichia coli cells. In this technique, the inoculated soil is heated to 500 C for several seconds at Martian ambient pressure and the sublimate, collected by a cold finger, then analyzed using high performance liquid chromatography. Methylamine and ethylamine, produced from glycine and alanine decarboxylation, were the most abundant amine compounds detected after pyrolysis of the cells. A heating cycle similar to that utilized in our experiment was also used to release organic compounds from the Martian soil in the 1976 Viking gas chromatography/mass spectrometry (GC/MS) pyrolysis experiment. The Viking GC/MS did not detect any organic compounds of Martian origin above a level of a few parts per billion in the Martian surface soil. Although the Viking GC/MS instruments were not specifically designed to search for the presence of living cells on Mars, our experimental results indicate that at the part per billion level, the degradation products generated from several million bacterial cells per gram of Martian soil would not have been detected.

Glavin, Daniel↗
NASA NTRS1999

Lithium-Ion Batteries for Aerospace Applications

This presentation reviews: (1) the goals and objectives, (2) the NASA and Airforce requirements, (3) the potential near term missions, (4) management approach, (5) the technical approach and (6) the program road map. The objectives of the program include: (1) develop high specific energy and long life lithium ion cells and smart batteries for aerospace and defense applications, (2) establish domestic production sources, and to demonstrate technological readiness for various missions. The management approach is to encourage the teaming of universities, R&D organizations, and battery manufacturing companies, to build on existing commercial and government technology, and to develop two sources for manufacturing cells and batteries. The technological approach includes: (1) develop advanced electrode materials and electrolytes to achieve improved low temperature performance and long cycle life, (2) optimize cell design to improve specific energy, cycle life and safety, (3) establish manufacturing processes to ensure predictable performance, (4) establish manufacturing processes to ensure predictable performance, (5) develop aerospace lithium ion cells in various AH sizes and voltages, (6) develop electronics for smart battery management, (7) develop a performance database required for various applications, and (8) demonstrate technology readiness for the various missions. Charts which review the requirements for the Li-ion battery development program are presented.

Surampudi, S.↗
NASA NTRS2010

Performance Characterization of High Energy Commercial Lithium-ion Cells

The NASA Glenn Research Center Electrochemistry Branch performed characterization of commercial lithium-ion cells to determine the cells' performance against Exploration Technology Development Program (ETDP) Key Performance Parameters (KPP). The goals of the ETDP Energy Storage Project require significant improvements in the specific energy of lithium-ion technology over the state-of-the-art. This work supports the high energy cell development for the Constellation customer Lunar Surface Systems (LSS). In support of these goals, testing was initiated in September 2009 with high energy cylindrical cells obtained from Panasonic and E-One Moli. Both manufacturers indicated the capability of their cells to deliver specific energy of at least 180 Wh/kg or higher. Testing is being performed at the NASA Glenn Research Center to evaluate the performance of these cells under temperature, rate, and cycling conditions relevant to the ETDP goals for high energy cells. The cell-level specific energy goal for high energy technology is 180 Wh/kg at a C/10 rate and 0 C. The threshold value is 165 Wh/kg. The goal is to operate for at least 2000 cycles at 100 percent DOD with greater than 80 percent capacity retention. The Panasonic NCR18650 cells were able to deliver nearly 200 Wh/kg at the aforementioned conditions. The E-One Moli ICR18650J cells also met the specific energy goal by delivering 183 Wh/kg. Though both cells met the goal for specific energy, this testing was only one portion of the testing required to determine the suitability of commercial cells for the ETDP. The cells must also meet goals for cycle life and safety. The results of this characterization are summarized in this report.

Schneidegger, Brianne T.↗
NASA NTRS1971

Heat sterilizable impact resistant cell development

Developments in the design and fabrication of 25 AH, 5AH, 70 AH, and 25 AH high impact cells and batteries are reported along with the development of high cycle life, low impact cells. Discussions of the performance and failure modes are included.

Jordan, A. W.↗
NASA NTRS1973

Non-gassing nickel-cadmium battery electrodes and cells: Testing of 25 Ah cells

The testing of 30 practical size, experimental 25 ampere hour cells constructed as part of an earlier negative limited cell development program is discussed. The test results showed that the negative limited cell is a possible means of developing a long-lived secondary cell. The cells were tested for 500 cycles using an accelerated regime approximating a 90-minute orbit period. Three groups of ten cells were tested at 0,25, and 40 C. The cycle data showed that the negative limited cells had higher degradation rates at the higher operating temperatures. At the conclusion of 500 cycles, the three groups had average capacities of 16.83, 12.74, and 5.71 ampere hours for testing at 0, 25, 40 C, respectively. The conditioning capacities of these cells was in the 25 ampere hours range. The internal cell pressures of the three groups was also temperature dependent and was, in general, in the 2 psig range during the course of the test program. No periodic variation of the internal pressure with the state-of-charge was observed except with some cells tested at 40 C.

Luksha, E.↗
NASA NTRS1978

Ultraviolet irradiation at elevated temperatures and thermal cycling in vacuum of FEP-A covered silicon solar cells

Silicon solar cells covered with FEP-A were irradiated in vacuum with ultraviolet light and then subjected to thermal cycling. These accelerated laboratory conditions are believed to be equivalent to those experienced by FEP-A covered cells on the ATS-6 spacecraft and the results indicate a probable mechanism for the faster degradation of the FEP-A covered cells. Heat-bonded FEP-A covers apparently embrittle when exposed to four months of space UV radiation at elevated temperatures, and crack when subjected to thermal cycling during the eclipse period. Low energy proton radiation can then penetrate to the junction of the cell causing degradation of the open circuit voltage and maximum power to occur. An alternate method of application of FEP-A, such as with adhesives, may prevent such cracking.

Broder, J. D.↗
NASA NTRS1985

The failure mechanism of a nickel electrode in a nickel-hydrogen cell

Studies on a number of types of nickel electrodes after cycle failure in a Ni/H2 cell showed that the failure is due to the loss of high rate discharge capability rather than an absolute capacity loss. The failure mechanism is speculated to be a combination of migration of the active material away from the current collecting nickel sinter, increased porosity of the active material caused by cycling, and an electrical isolation process of the active material during discharge.

Lim, H. S.↗